Incidental Gastric Neuroendocrine Tumor on Histology: What Should the Gastroenterologist Do Next?

Gastric neuroendocrine tumors (NETs) are increasingly diagnosed as incidental findings during upper gastrointestinal endoscopy. For the gastroenterologist, the crucial challenge is not only at the time of endoscopic recognition but also when the pathology report states “well-differentiated gastric NET”. At that moment, the key clinical question is how to manage it correctly. Gastric NETs are biologically heterogeneous, and their management depends primarily on the pathophysiological setting in which they arise. Type 1 tumors develop in chronic atrophic gastritis and are usually indolent; type 2 tumors arise in the context of gastrinoma and MEN1; type 3 tumors are sporadic and carry a substantially higher metastatic risk. Consequently, the same histological label may correspond to profoundly different clinical scenarios. This review addresses what the gastroenterologist should do after receiving an incidental histological diagnosis of gastric NET, how to reconstruct the gastric background, when to suspect a sporadic type 3 lesion, how to select patients for endoscopic treatment versus staging or surgery, and how to interpret incomplete endoscopic resection. Particular attention is devoted to the emerging concept of proton pump inhibitor-associated gastric NETs, which may represent a distinct gastrin-driven subgroup with lower malignant potential than truly sporadic type 3 tumors. A practical algorithm and a clinicopathological comparison of the classic three gastric NET types are provided to support decision-making in daily practice.